Tamper-evident envelope with indicia-forming cohesive layers

Abstract

An envelope with a pressure sensitive seal containing a hidden printed message which is revealed when the seal has been opened. The unsealed edges of the envelope each have an anchor coating covered by a cohesive layer. The message is formed by voids in the cohesive layer on one edge. Cohesive layers adhere to the anchor coatings on both edges, and seal the envelope as desired. The cohesive layers have a stronger affinity for each other than for the anchor coating. The message is revealed as the cohesive layer containing voids separates from the anchor coating causing the disruption of the anchor coating, when the sealed envelope is opened.

We claim: 
     
       1. A tamper-evident envelope, comprising: (a) a pouch formed from at least one sheet of impact resistant material, said pouch having a plurality of edges sealed along all but one remaining edge;   (b) said remaining edge defining an access opening through which items can be placed into said pouch:   (c) said remaining edge having upper and lower inner surfaces;   (d) said upper inner surface being covered with a translucent upper anchor coating, and said lower inner surface being covered with a translucent lower anchor coating;   (e) said upper anchor coating being covered with a cohesive layer;   (f) said lower anchor coating being covered with said cohesive layer in a predetermined pattern bearing characteristic indicia, so that when said cohesive layers of said remaining edge are pressed together, a translucent seal closing the pouch is formed obscuring said characteristic indicia;   (g) said cohesive layer on the lower inner surface being interrupted by predetermined void regions, said void regions defining said indicia which convey a message that the seal has been broken; and   (h) said cohesive layers having a greater affinity for each other than for the anchor coatings and the affinity between said interrupted cohesive layer on said lower surface and said anchor coating being less than the affinity between said non-interrupted cohesive layer on said upper surface and said anchor coating, so that said cohesive layer covering said anchor coating on said lower inner surface is pulled away from said anchor coating to reveal said indicia when said inner surfaces are separated after being cohesively sealed,   whereby any attempt to break said translucent seal results in the disruption of said cohesive layers and said anchor coatings causing said characteristic indicia to be revealed.   
     
     
       2. The envelope of claim 1, wherein the act of pulling said cohesive layer from said anchor coating causes the disruption of said anchor coating. 
     
     
       3. The envelope of claim 2, wherein said anchor coating beneath said predetermined void regions is not disrupted. 
     
     
       4. The envelope of claim 3 further comprising a removable means interposed between the cohesive layers to prevent cohesion before sealing. 
     
     
       5. The envelope of claim 1, wherein at least one of said cohesive layers is translucent. 
     
     
       6. The envelope of claim 5, wherein said cohesive layer is a preparation comprising a soft latex. 
     
     
       7. The envelope of claim 1, wherein said translucent anchor coating is a preparation comprising an acrylic copolymer and polyvinyl acetate. 
     
     
       8. A tamper-evident envelope, comprising: (a) a pouch formed from at least one sheet of pliable film, said pouch having a plurality of edges sealed along all but one remaining edge;   (b) said remaining edge defining an access opening through which items can be placed into said pouch;   (c) said remaining edge having mutually confronting inner surfaces;   (d) anchor coatings covering each of said inner surfaces of said remaining edge, at least one of said anchor coatings being translucent;   (e) cohesive layers covering each of said anchor coatings;   (f) at least one of said anchor coatings being covered with said cohesive layer in a predetermined pattern bearing characteristic indicia, so that when said cohesive layers of said remaining edge are pressed together, a translucent seal closing the pouch is formed; and   (g) said cohesive layers having a greater affinity for each other than for said anchor coatings, and the affinity between said patterned cohesive layer and said anchor coating being less than the affinity between said non-patterned cohesive layer and said anchor coating,   whereby any attempt to break said translucent seal results in the disruption of said anchor coating and said cohesive layers as said patterned cohesive layer is pulled away from said anchor coating causing the exposure of said characteristic indicia.   
     
     
       9. The envelope of claim 8, wherein said translucent anchor coating is a preparation comprising an acrylic copolymer and polyvinyl acetate. 
     
     
       10. The envelope of claim 8, wherein at least one of said cohesive layers is translucent. 
     
     
       11. The envelope of claim 10, wherein said cohesive layer is a preparation comprising a soft latex. 
     
     
       12. The envelope of claim 10, further comprising a removable means interposed between the cohesive layers to prevent cohesion before sealing.